Filed of the Invention
The present invention relates to a charging control device, and more particularly to a charging control device used for charging a battery of a plug-in hybrid car or an electric car.
Description of the Related Art
A charger that charges a high voltage battery for driving, mounded in an electric vehicle with an external charging function, such as a plug-in hybrid car (PHEV) or an electric car (EV), has used a method (normal charging method) of charging the high voltage battery by using an external power source of AC 100/200 V to generate direct current of high voltage with an AC/DC converter or the like in the electric vehicle.
Unfortunately, in the method, it takes about 7 hours by using an external power source of AC 200 V, or about 14 hours by using that of AC 100 V to fully charge the high voltage battery.
To solve this disadvantage of the normal charging method in which a charging time is long, a boost charger for charging a high voltage battery in a short time has been provided.
The boost charger uses a method of charging a high voltage battery by directly supplying direct current at a high voltage of DC 300 V or more and with large electric power to the high voltage battery from an external power source. The boost charger applies a direct current at 300 V or more to a connector socket for boost charging provided in an electric vehicle, and to a terminal of a connector plug (charging gun) of an external power source, inserted into the connector socket.
In this way, the boost charging of a high voltage battery using an external power source applies higher voltage than that in the normal charging method to the connector plug or the connector socket, for charging, and thus electric current with large electric power tends to flow in the case of short-circuiting or getting an electrical shock. Thus, a more sufficient safety measure is required as compared with the normal charging method. For example, if a charging contactor provided in a charging circuit in an electric vehicle melts, the connector may receive output voltage of the high voltage battery after being removed, depending on a state of the circuit.
For that, when high voltage is applied to a terminal of a charging connector, for example, a connector plug (gun) of a charger is locked to be prevented from being removed (refer to Japanese Patent Laid-Open No. 2013-020732, for example).
Although a conventional electric vehicle determines melting of a charging contactor after charging is finished, the charging contactor is controlled to open when it is determined that there is no melt to allow a charging connector to be removed.
A conventional electric vehicle cannot allow a charging contactor to open even after charging is finished if the charging contactor melts, and thus high voltage remains applied to a charging connector so that the charging connector cannot be removed. Thus, when being moved by a wrecker or the like, for example, the electric vehicle has to be towed away while the charging connector remains connected. As a result, there is a problem in that an external charger may be disassembled to be unable to be used.